Code-division multiple access (CDMA) communication systems are well known. One exemplary CDMA communication system is the so-called IS-95A which is defined for use by in North America by the Telecommunications Industry Association (TIA). For more information on IS-95A, see TIA/EIA/IS-95-A, Mobile Station-Base-station Compatibility Standard for Dual Mode Wideband Spread Spectrum Cellular System, March 1995, published by the Electronic Industries Association (EIA), 2001 Eye Street, N.W., Washington, D.C. 20006. Soft handoff in CDMA communication systems such as IS-95A is a well known technique to improve the capacity of such a CDMA communication system. When in soft handoff, simultaneous up-and down-links are created between a subscriber unit and two or more cell sites.
Prior to initiating a soft handoff, a mobile station in communication with a source base-station determines the detection quality of a downlink (base-station to mobile station) transmission not only from the source base-station but also candidate target base-stations. The downlink transmission received and analyzed by the mobile station from the various base-stations is called the pilot channel. Generally stated, if the mobile station determines that the signal strength of the pilot channel transmitted by a target base-station exceeds a particular threshold or detection criteria, the mobile station will signal measurement data to the infrastructure, which in turn will send messages back to the subscriber to initiate a soft handoff. However, conditions associated with the transmission environment and setting of equipment parameters, create imbalance between the uplink and downlink signals. Since downlink measurements dictate when soft handoff is established, it may either be late or premature for optimizing communication in the uplink. Therefore, communication to the mobile station and the performance of the CDMA communication system as a whole may not actually benefit from being in soft handoff.
Thus, a need exists for an improved method and apparatus which overcomes the deficiencies of the prior art.